CJS build duplicates module state (cached style map, stencilBuildEvents) across entry points

[gavmck]

Summary

In the CJS build, the package's entry points each inline their own copy of the stateful style-dependencies module, so module-level singletons are duplicated rather than shared. A consumer that creates the plugin from ./vite but reads getComponentStyleDependencies() / stencilBuildEvents from the main entry (.) sees an empty map, because the plugin populated a different cached.

Detail

• Main entry index.cjs defines its own var cached = null and exports getComponentStyleDependencies / rebuildStyleMap / stencilBuildEvents bound to it.
• vite.cjs defines a separate var cached = null and its own stencilBuildEvents emitter, and its plugin's buildStart calls rebuildStyleMap against that copy.
• Neither CJS entry require()s a shared chunk for the style-dependencies/build-events modules — each is fully inlined.

So:

vite.cjs  rebuildStyleMap → cached.byStyle.size = 100
index.cjs getComponentStyleDependencies() → cached.byStyle.size = 0   // different instance

The ESM build is fine — index.js and the vite plugin both import the shared chunk-*.js that owns cached, so state is shared.

Impact

@stencil/storybook-plugin@0.7.0 relies on exactly this cross-entry sharing for SCSS HMR: it builds the Stencil plugin from @stencil-community/unplugin-stencil/vite and reads the style→component map from @stencil-community/unplugin-stencil. Under CJS (how Storybook loads its preset) the map is always empty, so editing a component's .scss never triggers a rebuild. (Tracking issue on their side: stenciljs/storybook#54.)

Suggested fix

In the CJS build, have the entry points resolve the style-dependencies and build-events modules to a shared chunk (as the ESM build does) so cached and stencilBuildEvents are true singletons across ., ./vite, ./rollup, etc.

Environment

• @stencil-community/unplugin-stencil 0.5.2 (latest)
• consumed via @stencil/storybook-plugin 0.7.0 + storybook 10.2.19 (Vite builder)